Nonlinear dynamic response and bifurcation of asymmetric rotor system supported in axial-grooved gas-lubricated bearings

Sha, Li; Lü, Yanjun; Zhang, Yongfang; Luo, Hongbo; Wang, Song; Kan, Xuanen

doi:10.1177/14613484211052714

Cited by 3 publications

(1 citation statement)

References 31 publications

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“…Zharilkassin et al [18], using Bogolyubov's asymptotic method and numerical methods, constructed a gyroscopic rigid unbalanced rotor with nonlinear cubic damping and nonlinear rigidity of the elastic support. Li et al [19] studied the dynamic characteristics of an asymmetric rotor system supported by axial-grooved gas-lubricated bearings by using the hybrid numerical model.…”

Section: Introductionmentioning

confidence: 99%

The Nonlinear Dynamic Characteristics of an Industrial Turbine Engine with Eccentric Squeeze Film Dampers

Zeng,

Luo,

Wang

et al. 2023

Applied Sciences

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Squeeze film dampers are often used to suppress vibration in turbine engines and play an important role in rotor systems. In this paper, the nonlinear dynamic characteristics of an industrial turbine engine fitted with squeeze film dampers are investigated with the static eccentricity of the SFDs. A recently developed time domain technique that combines the finite element method and the fixed interface modal synthesis method is applied to predict the nonlinear unbalance response of the industrial turbine engine under different unbalanced and static eccentricity configurations. By comparing the results obtained using SFDs with and without static eccentricity, it can be concluded that increasing the static eccentricity of the SFDs promotes non-periodic motion, while an increase in the unbalance level promotes the jump phenomenon. The efficiency of the rotor system would improve with an appropriate amount of unbalance applied to compressor IV, resulting in a reduction in the vibration level. If static sprung eccentricity occurs, the center of the journal orbit would be offset from the SFD center, rendering it inefficient or even leading to rub impact. Therefore, it is crucial to control the static eccentricity of the SFDs for optimal performance. The time domain technique is verified by the experimental results reported in the literature.

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Section: Introductionmentioning

confidence: 99%

The Nonlinear Dynamic Characteristics of an Industrial Turbine Engine with Eccentric Squeeze Film Dampers

Zeng,

Luo,

Wang

et al. 2023

Applied Sciences

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Numerical solution of the boltzmann-based lubrication equation for multi-leaf gas microbearing with different load configurations

Wu,

Xi,

Cao

et al. 2024

Proceedings of the Institution of Mechanical Engineers, Part J:

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The lubrication characteristics of multi-leaf aerodynamic microbearings influence the reliable operation and service life of microfluidic devices directly. Based on the linearized Boltzmann rarefaction model with three adjustable coefficients, the dynamic gas film pressure, film thickness and Poiseuille flow ratio can be expressed as two superimposing static and complex perturbed terms. The modified Reynolds equation including complete variable disturbance of multi-leaf microbearings for different load configurations are derived, which solved by the finite difference algorithm, partial derivative method and over-relaxation iteration simultaneously. The effects of preload factor, pad location and perturbation frequency on load capacity and dynamic coefficients of multi-leaf/cylindrical microbearings are investigated in detail. Results indicate that the gas film peak pressure of multi-leaf microbearings is higher at greater pad preload, and the direct stiffness coefficients of multi-leaf microbearing for load between pad are larger because of pumping effect within axial grooves that decrease the degree of rarefied gas flow.

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Theoretical and Experimental Study on the Performance of Hermetic Diaphragm Squeeze Film Dampers for Gas-Lubricated Bearings

Wang,

Zhang,

Han

et al. 2024

Chin. J. Mech. Eng.

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Low damping characteristics have always been a key sticking points in the development of gas bearings. The application of squeeze film dampers can significantly improve the damping performance of gas lubricated bearings. This paper proposed a novel hermetic diaphragm squeeze film damper (HDSFD) for oil-free turbomachinery supported by gas lubricated bearings. Several types of HDSFDs with symmetrical structure were proposed for good damping performance. By considering the compressibility of the damper fluid, based on hydraulic fluid mechanics theory, a dynamic model of HDSFDs under medium is proposed, which successfully reflects the frequency dependence of force coefficients. Based on the dynamic model, the effects of damper fluid viscosity, bulk modulus of damper fluid, thickness of damper fluid film and plunger thickness on the dynamic stiffness and damping of HDSFDs were analyzed. An experimental test rig was assembled and series of experimental studies on HDSFDs were conducted. The damper fluid transverse flow is added to the existing HDSFD concept, which aims to make the dynamic force coefficients independent of frequency. Although the force coefficient is still frequency dependent, the damping coefficient at high frequency excitation with damper fluid supply twice as that without damper fluid supply. The results serve as a benchmark for the calibration of analytical tools under development.

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Nonlinear dynamic response and bifurcation of asymmetric rotor system supported in axial-grooved gas-lubricated bearings

Cited by 3 publications

References 31 publications

The Nonlinear Dynamic Characteristics of an Industrial Turbine Engine with Eccentric Squeeze Film Dampers

The Nonlinear Dynamic Characteristics of an Industrial Turbine Engine with Eccentric Squeeze Film Dampers

Numerical solution of the boltzmann-based lubrication equation for multi-leaf gas microbearing with different load configurations

Theoretical and Experimental Study on the Performance of Hermetic Diaphragm Squeeze Film Dampers for Gas-Lubricated Bearings

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